THE BODY ORGANIZATION 23 



4. How does the general work of cells differ from their special 

 work ? Define absorption, excretion, and assimilation as applied to 

 the cells. 



5. Compare the conditions surrounding a one-celled animal, living 

 in water, to the conditions surrounding the cells in the body. 



6. What is meant by the term "environment" ? How does man's 

 environment differ from that of a fish ? 



7. What is the necessity for a nutrient fluid in the body ? 



8. Why is the maintenance of life necessarily the chief aim of all 

 the activities of the boay ? 



9. State the twp^main problems in the study of the body. 



PRACTICAL WORK 



Observations. i. Make some scrapings from the inside of the 

 cheek with a dull knife and mix these with a little water on a glass 

 slide. Place a cover-glass on the same and examine with a compound 

 microscope. The large pale cells that can be seen in this way are 

 a variety of epithelial cells. 



2. Mount in water on a glass slide some thin slices of cartilage and 

 examine first with a low and then with a high power of microscope. 

 (Suitable slices may be cut, with a sharp razor, from the cartilage found 

 at the end of the rib of a young animal.) Note the small groups of 

 cells surrounded by, and imbedded in, the intercellular material. 



3. Mount and examine with the microscope thin slices of elder pith, 

 potato, and the stems of growing plants. Make drawings of the cells 

 thus observed. 



4. Examine with the microscope a small piece of the freshly sloughed 

 off epidermis of a frog's skin. Examine it first in its natural condition, 

 and then after soaking for an hour or two in a solution of carmine. 

 Make drawings. 



5. Mount on a glass slide some of the scum found on stagnant water 

 and examine it with a compound microscope. Note the variety and 

 relative size of the different things moving about. The forms most 

 frequently seen by such an examination are one-celled plants. Many 

 of these have the power of motion. 



6. Examine tissues of the body, such as nervous, muscular, and glan- 

 dular tissues, which have been suitably prepared and mounted for micro- 

 scopic study, using low and high powers of the microscope. Make 

 drawings of the cells in the different tissues thus observed. 



